Pneumatic gun mechanism



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PNEUMATIC GUN MEcHANIsM Filed Deo. 8 1953 INVENToRs BY AGE/vr UnitedStates Patent PNEUMATIC GUN MECHANISM Charles E. Calling, El Cajon, andWilbur G. Sherman, San Diego, Calif.

Application .December 8, 1953, Serial No. 396,878

1 Claim. (Cl. 124-11) The present invention relates generally to apneumatic gun and relates more specifically to a pneumatic gun having apressure differential operated pneumatic charge releasing mechanism foruse in the propulsion of a suitable missile or projectile therefrom.

Heretofore, many attempts have been made to devise valve mechanisms andoperating means therefor for use in pneumatic guns that are designed forthrowing suitable missiles therefrom. Many of these prior devices havehad a major disadvantage in that Vvarious supplemental structures wereused in order to force a valve to an open position to admit a pneumaticcharge to the bore of a barrel. Such valves often had to be openedagainst the force of the pneumatic charge, thus consuming a`considerable amount of energy that might otherwise be used forpropulsion of a projectile. Additionally, prior arrangements ofpneumatic guns have frequently required that a pneumatic charge beconducted through several ninety degree turns before reaching a pointrearwardly oi' a projectile. Each of such turns reduces the electiveforce of the charge in the propulsion of the projectile.

Accordingly, it is one object of the present invention to provide apneumatic gun operating mechanism that is simple in construction,compact in design, eicient in operation and :adapted to propel asuitable missile or the like therefrom.

It is another object of the present invention to provide a pneumatic gunoperating mechanism wherein pneumatic pressure differentials areutilized to effect opening of a suitable valve mechanism fortransmitting a pneumatic charge to a barrel bore to propel a missile orprojectile therefrom.

It is a further object of the invention to provide a pneumatic gunhaving a novel sear operating and releasing mechanism.

It is still `a further object of the present invention to provide apneumatic gun wherein a pneumatic charge may be delivered directly to abarrel bore thereoi` in a manner and from a position that is axiallydisposed relative to said bore.

It is another object of the present invention to provide a pneumatic gunhaving novel means for immediately and pneumatically recharging said gunin preparation for release of a new charge and propulsion of a nextfollowing projectile.

Other and further important objects of the present inf vention willbecome apparent in the disclosures of the following specifications,appended claim and accompanying drawing wherein:

Fig. l is a top plan view of the pneumatic gun of the present invention;

Fig. 2 is an enlarged fragmentary sectional View of the operatingmechanism of the present pneumatic gun as taken substantially asindicated by line 2 2, Fig. l;

Fig. 3`is an enlarged fragmentary sectional view of the sealing meansfor a breech valve as taken substantially as indicated by line 3 3, Fig.2; and

Fig. 4 is a sectional View through a portion of a trigger 2,780,213Patented Feb. 5,

mechanism as taken substantially a-s indicated by line 4-4,' Fig. 2. v

Referring to the drawing by reference characters where-t in likecharacters indicate like parts, the pneumatic gun of the presentinvention is shown as indicated generally at 10. As shown, the gun 19includesy a substantially` cylindrical breech casing 11, that isprovided with'` an axial extending bore 12. The bore 12 has a taperedreduced diameter portion 13 on which an axial extending portion 14 isdisposed. The portion 14 is provided with external threads 15 that matewith similar threads on the inner end 16 of a barrel 17. The barrel 17has a suitable bore 18 therethrough, a projectile or missile, indicatedgenerally at P, being adapted for reception in the inner end of the bore18.

The rearward end of the breech casing 11 is provided with suitableexternal threads 19 that are adapted to receive a rear closure member 20from which a handle 21 depends. A cylindrical sleeve member 22 isdisposed in the rearward end of the bore 12, an outwardly extendingflange 23, formed on the rearward end of the sleeve 22, being adaptedfor reception intermediate the rearward end of the breech casing 11, anda rear wall or abutment 24 of the closure member 2t). The sleeve 22 issealed with respect to the bore 12 as by a suitable O-ring 25 which isadapted for reception in anl annular groove 26 formed on the peripheryof the sleeve 22 adjacent the inner end thereof. This inner end of thesleeve 22 is closed as by a partition 27 which extends transversely ofthe bore 12. The sleeve 22 is further provided with an internal axiallyextending secondary sleeve 275, the interior diameterof which definesanV axially extending recess 29, one end of whichV is closed by thepartition 27. VThe space defined between the sleeves 22 and 28 may belled with solid material or removed, as shown, to lighten the gunstructure.

An annular breech valve member 30 is normally disposed in the inner endof the bore 18 and adapted normally to seal 4otf this inner end. Thisbreech valve member 30 is provided with an annular groove 31, Fig. 3,about the inner end thereof, in which an O-ring 32 is adapted to bedisposed. The O-ring 32 has a normally extending, axially relativelyshort groove 33, in the portion thereof adjacent the bore 12, in whichseveral turns of a wire or cord are positioned. For a purpose to behereinafter more fully described, the cord 34 serves to maintain theO-ring 32 in the groove 31 and deforms the O-ring 32 until the groove 33lassumes the position shown in Fig. 3. Also, for a purpose to behereinafter more fully described, the end of the breech valve 30adjacent the inner end of the bore V1S is beveled as at 35. The otherend of the breech valve 3GV is reduced in diameter and terminates in anaxially extending boss 36 that is threadably engaged on an axiallyextending shaft 37. y

As` shown primarily in Fig. 2, the shaft 37 extends rear' wardly andthrough an axial opening 38 in the partition 27, ya sealing member 39being disposed in the partition 27 and adapted to surround and engagethe shaft 37. A n actuating pist-on 49 is disposed on the end of theshaft 37 that extends through the opening 38, this piston having aVperipheral sealing member 41 that is adapted to VmakeY sliding contactwith the 4recess 29 formed within the sleeve 28. It is to lb e notedthat the diameter of the piston 4t), together with the sealing member41, is slightly larger than the diameter of the breech valve`36 and theO-ring 32, t-o eiect opening of the breech valve in a manner to beyhereinafter more fully described.

T-he pneumatic gun ofthe present invention is thus provided with acharge pressure chamber 42 that is deiined within the bore 12intermediate the partition 27 and the ybreech valve 30. An actuatingpressure chamber 43 is formed intermediate one side of the piston 40 andthe partition 27, there being an orifice 44 through the partition 27 toprovide a restricted communication 'between the charge pressure chamber42 and the actuating pressure chamber 43. Al back-up or cushion chamber45 is formed intermediate another side of the piston 4@ and the rearwall 24 of the closure member 20, a compression spring 46 beingdispo-sed in this cushion chamber 45 and acting intermediate the rearwall 24 of the closure member and a iitting 47 adjacent the piston 40,this spring serving to -bias the piston 40 leftwardly, as seen in Fig. 2and, through the shaft 37, bias the lbreech valve 39 toward the closedposition as also `s-hown in Fig. 2. The piston 40 provides a -movablewall between the actuating pressure chamber 43 and the cushion chamber45. For purposes of description, the chambers 43 and 45 are combined andtermed a secondary chamber with chamber 42 being referred to as aprimary chamber.

An extension 48 of the shaft 37 extends Ifrom the piston 40 through thetting 47 and -is slida-bly positioned in an axial bore 49 formed in theclosure member 2t). The rearward end of this extension is normallyspaced from the end of the bore 4%, and is provided with a conical endportion 50 that may have an angular relationship of sixty degrees, forexample, relative to the axis of the extension 48. A sear 51 ispositioned in a cylindrical opening 52, in theclosure member 20 and`handle 21, this opening 52 being disposed normal to the axis yof `theextension 48 and bore 44. The upper end of the sear 51 is provided witha conical end portion 53 that is adapted to extend into the Vbore 49 andmate with the conical end 50 formed on the extension 43. For thispurpose, it may be seen that the conical end 53 may have `an angularrelatioiiship of thirty degrees relative to the axis of the sear 5 Thesear 51 has a reduced `diameter rod portion 54 that extends through thelower end of the cylindrical opening 52 and is journalled in a bushing55 which is in turn threadably disposed in the lower end of thecylindrical opening 52. A compression spring 56 extends intermediate theinner end of the bushing 55 and the sear 51, normally to bias the sear51and the end 53 thereof into engagement with the end 50 of the extension48. A catch member 57, that is positioned approximately normal to anoperating arm 58 of a trigger 59, is adapted to engage a protrudingportion 60 of the rod 54 thereby to maintain the rod 54 in its upwardposition with the sear 51 in position for engagement of the end 53thereof with the end 50 of the extension 48.

The arm 58 of the trigger 59 is provided with wing portions 61, Fig. 4,that extend rearwardly on each side of the handle 21 and are pivoted onpins 62 which extend into rthe handle 21. A -compression spring 63, Fig.2, is disposed. intermediate the handle 21 and the trigger 59, normallyto bias the trigger 59 and the arm 58, together with the catch 57 to theposition shown in Fig. 2. A trigger guard 64 is also disposed about t-hetrigger 59 in the usual manner and for the usual purpose.

For a purpose to be hereinafter more fully described, the inner wall 24of' the closure member 2t) may be provided with 'a resilient bumpermember 65 that may be secured thereto as by gluing or lthe like andadapted to 'be engaged by the piston 40 upon axial movement thereof.

` A source of compressed gas which may be carbon dioxide, for example,is contained within a suitable supply cylinder 66 which is mounted, asyby a bracket 67, to the exterior of the breech casing 11. The cylinder66 may be provided with a suitable iiller valve arrangement 68 at oneend thereof, and a discharge control valve 69 at the other end thereof.While the cylinder 66 is shown as'disposed above the barrel 17 of thepneumatic gun, it is to `be understood that this position is merely byway of example and that the cylinder 66 may either be secured to anyother portion of the gun or arranged completely remote therefrom. Thevalve 69 has a litt-ing 70 that connects with a tube 71 that extendsfrom the tting and communicates with the charge pressure chamber 42 asat 72. The tube 7i is necessarily relatively small in diameter toprovide a flow restricting communication between the cylinder 66 and thecharge pressure chamber 42. The charge pressure chamber 42 is fittedwith a guage 73, Fig. l, as by a fitting 74, Fig. 2, to enable theoperator of the gun to determine the pressure existing in the chargepressure chamber 42.

In operation, when the valve 69 is opened, the gas under pressure fromthe cylinder 66 is admitted through the tube 71 to the chamber 42 andbleeds through the orifice 44 into the actuating pressure chamber 43.inasmuch as the eifective area of the piston 40 is greater than theeffective area of the breech valve 30, there exists a differential inpressure acting upon `the piston 40 tending to compress the spring 46.rThis tendency for compression of the spring 46 is resisted by the sear51, and upon movement of the trigger 59 to remove the catch 57 from itsengagement with the protruding end 6) of the rod 54, the force of thisdifferential pressure will move the piston 4t), breech valve 36, rod 37and extension 48 rearwardly, compressing the spring 46 and moving thesear 51 out of its normal position by action of the conical end 5t!against the conical end 53. Upon initial movement of the piston 40 andinitial opening of the breech valve 34B, pressures acting about `thebreech valve 30 are substantially cqualized, thus causing a greatereffective force on the piston 40 to force complete opening of the valveSi). The beveled end 35 of the breech valve 30 permits immediatetransmission of the charge within the charge pressure chamber 42 to theinner end of the bore i8 and eliminates any tendency to withdraw theprojectile P into the chamber 42 when the breech valve 3i) is opened tothe position shown by the dotted lines, in Fig. 2.

As the piston 49 -together with the breech valve 30 moves to the dottedline position in Fig. 2, air contained in the cushion chamber 45 will becompressed, thu-s providing a pneumatic cushion for the rearwardmovement of the breech valve and piston assembly. Additionally, due tothe restricted communication between the charge pressure chamber 42 andthe actuating pressure chamber 43, as dened by the orifice 44, uponmovement of the breech valve and piston assembly, the force of the gaspressure in the chamber 43 is soon expended in the initial opening ofthe breech valve 30 thereby creating a raried atmosphere and asemi-vacuum in the chamber 43 to thus provide additional cushioning lformovement of the breech valve and piston assembly. It has been found thatapproximately 800 pounds of gas pressure is satisfactory to adequatelypropel the projectile from the gun. Should additional pressure be used,the piston 40 may travel rearwardly a greater distance toward thecushion chamber 45 Vthan would be expected under normal circumstances.In such a case, the side of the piston 40 adjacent the cushion chamber45 would engage the resilient cushion member 65 thus avoiding any metalto metal contact that might otherwise injure the parts of the mechanism.

When the charge has been expended from the chamber 42, the spring 46tends to return the breech valve 30 and piston 40 assembly toward theposition shown in Fig. 2. This action occurs almost simultaneously withthe release of the charge from the chamber 42, thus permitting the sear51 to return to its original position at the rearward end of theextension 48 and allowing the catch 57 to move to its original position,in engagement with the extended end 60 of the rod 54. The gun mechanismis next readied for the following discharge by continued communicationbetween the cylinder 66 and the charge pressure chamber 42 through thetube 71. In view of the restricted communication provided by the tube 71between the cylinder 66 and the chamber 42, this next charge will buildup rather slowly and little pressure will be lost during the opening andclosing of the breech valve 30 in view of the short duration duringwhich the breech valve is open. Thus successive shots may be madewithout the necessity for manually recharging the chamber 4Z. In someinstances, it may be desirable to admit only the desired pressure to thechamber 42 by opening the valve 69, and then closing this valve when thedesired charge pressure is obtained. In such instances, the pressure inthe chamber 42 may be read directly through use of the gauge 73 and thevalve 69 closed following the establishment of the desired pressure inthis charge pressure chamber.

As hereinbefore described, the O-ring 32 surrounding the periphery ofthe breech valve 31B is maintained in position by means of the wire orcord 3d. Thus, any tendency for the charge within the chamber. 4t2 tounseat the O-ring 32 and possibly discharge this O-ring through the bore18 of the barrel 17 is completely eliminated. It is to be noted that thegroove 33 in which the cord 34 is disposed is actually deformed so thatthe entrance thereof is spaced radially inwardly from the out-erperiphery of the O-ring 32, thus to eliminate any malfuncsealing of theinner end of the bore 18.

In order to compensate for the recoil that may normally be expected inconnection with a pneumatic gun of the class described, as shown in Fig.2, it may be desirable to secure a loo-p 75 to the lower side of thebreech casing 11 as by welding or the like. This loop 75 may be engagedby a suitable buckle 76 or the like, that may be attached to one end ofa cable 77. The cable 77 may extend to some point on the ground or inassociation with a fixed structure and is adapt-ed to be attached atthis fixed point. Rearward movement of the pneumatic gun mechanism maythereby be taken up by the loop, buckle and cable arrangement ratherthan by the arms and other bodily portions of the user.

It may also be desirable to utilize other well known forms of recoilcompensating devices that may be attached to the barrel 17 or therearward closure member 20 of the mechanism; however, under normalconditions, such additional mechanism has not been found necessary asthe recoil encountered with the present pneumatic gun is suiciently lowas to enable the user to operate the gun without additional compensatingdevices.

Having thus described the invention and the present embodiment thereof,itis desired to emphasize the fact that many modification-s may beresorted to in a manner limited only by a just interpretation of thefollowing claim. f

We claim:

A pneumatic gun comprising, in combination: a breech casing; a barrelattached to`said casing and having a missile receivingrboretherethrough; =a charge pressure chamber formed in said casing adjacentan inner end of said barrel; a breech valve seat having a diameter equalto that of said bore and formed between said charge pressure chamber andsaid bore; a breech valve adapted for cooperation with said valve seatfor controlling tlow from said charge pressure chamber into said bore;means normally biasing said breech valve toward a closed position; anactuating pressure chamber formed in said casing axially adjacent tosaid charge pressure chamber; a partition disposed in said casing andseparating said chambers, said partition deniug a stationary wall foreach of said chambers; an orifice formed through said partition andproviding a restricted communicationV between said charge pressurechamber and said actuating pressure chamber; a piston disposed in saidactuating pressure chamber, one side of said piston forming a movablewall for one end of said actuating pressure chamber, said piston havingan effective area larger than the effective area of said breech valve; apneumatic cushion chamber formed in said casing on the other side ofsaid piston, said breech valve biasing means being disposed in saidcushion chamber ntermediate a stationary end of said cushion chamber andsaid other side of said piston; a bumper disposed on said stationary endof said cushion chamber, said bumper being adapted for engagement bysaid piston upon movement thereof and having an axial thickness greaterthan compressive limits of said biasing means for said breech valve; ashaft slidably disposed through said partition and interconnecting saidbreech valve and said piston; a source of gas under pressure; orificemeans for admitting said gas to said charge pressure chamber toestablish a charge therein; an extension formed on said shaft andextending from said piston; a conical end formed on said extension; asear having a matching conical end adapted for cooperation with saidextension conical end for maintaining said breech valve in a closedposition; spring means normally biasing said sear into contact with saidextension; locking means for securing said sear in said contactingposition and a trigger for releasing said locking means, whereby topermit said piston` to be moved in response to a pressure diierentialcreated by the differences in said eective areas thereby to move saidshaft and said extension, depress said sear against the force of saidspring means, open said breech valve and transmit said charge from saidcharge pressure chamber to said Vbore to propel said missile therefrom.

References Cited in the file of this patent UNlTED STATES PATENTSSherman et al. V M-ar. 30, 1954

